Separating vapors from gases by refrigeration



Nov. 28, 1933. M, AN 1,936,622

SEPARATING VAPORS FROM GASES BY REFRIGERATION Filed July 25, 1930 A TTORNEYS Patented Nov. 28, 1933 UNITED STATES SEPARATlNG VAPORS FROM GASES BY REFRIGERATION Mathias Frtlnkl, Augsburg, Germany, assignor to American Oxythermic Corporation, New York, N. L, a corporation of Delaware Application July 25, 1930, Serial No. 470,692, and in Germany July 27, 1929 9 Claims.

The invention relates to a process for separating vapors from a gaseous mixture and to an apparatus adapted to effect such a separation. More particularly, it relates to the removal of water vapor from air in a system utilizing cold accumulators in order to cool ingoing air and'to absorb cold from outgoing separated components,

and includes correlated improvements and dis-' coveries whereby this separation may be effected.

scribed in my copending application Serial No. 347,274, filed March 15, 1929, in which the vapors are separated continuously Within a condenser or Wet-cooler sprinkled with a refrigerating liquid, and cold exchange between fresh ingoing' gas and dried outgoing gas is effected by means of a pair of cold accumulators or regenerators through which the gas flows in a direction which is reversed periodically.

In the beginning the fresh gas which is to be treated is lead into one of the two cold accumulators. It loses its heat there and penetrates in a cooled state into the condenser-where it is freed from vapors. The dried gas enters into the second cold accumulator, loses its cold there and then leaves said accumulator. The direction of fiow is then reversed and the fresh gas is lead into the cold accumulator through which the dried gas has passed formerly.

The flow of fresh gas in a given direction through the first of the two cold accumulators is continued until it is warmed in order to evaporate the moisture condensed therein before a reversal of fiow may take place and a dried gas may be sent therethrough.

During the period between the moment when the effect of warm blowing mayfirst be noticed at the lower or cold end of the fresh gas cold accumulator until the thorough heating of the 4-9 same, the gas must be cooled within the condenser.

Consequently, during this period the gas takes up the cold not only in the first (fresh gas) cold accumulator but also in the condenser, the total absorbed amount of cold being greater than the cold accumulating capacity of the second (dried gas) cold accumulator. A large portion of the cold taken up by the gas in the condenser is consequently lost.

It is an object of the invention to obviate the foregoing disadvantages and to provide an improved method whereby loss of cold maybe reduced', if not entirely avoided.

Another object of the invention is to provide a process utilizing cold accumulators for cold exii A method of drying air and other gases is dechange, which is readily operable on a commercial scale and in which vapors are effectively removed with minimum loss of cold.

Another object of theinvention is to provide a process for the removal of vapors utilizing a wet cooler in combination with cold accumulators and in which the gaseous mixture first passes through a cold yielding zone, then through a wet cooler in direct contact with a refrigerating liquid, and thence through a cold absorbing zone. The process is also featured by a dividing of the gaseous mixture leaving the wet cooler and passing part through a cold accumulator and another part through an indirect heat exchanger in which the refrigerating liquid is partially cooled.

A further object of the invention is to provide an apparatus which includes a plurality of cold accumulators, a wet cooler or trickle condenser and an' indirect heat exchanger connected in operative relation to accomplish an effective separa-- tion of vapors from a gaseous mixture.

Other objects of the invention will in part be obvious and will in partappear hereinafter.

The invention accordingly comprises the several stepsand the relation of one or more of such steps with respect to each of the others, and the apparatus embodying features of construction, combinations of elements and arrange ment of parts which are adapted to'effect such steps, all as exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.

In the practice of the invention a refrigerating liquid, as a brine, is utilized to remove vapors from a gaseous mixture and reheated during passage through a specially designed wet cooler, and subsequently recooled by a part of the gaseous stream. which has been cooled and dried and divided out, or branched off from the main stream which passes to a cold accumulator. Thereby the quantity of gas leaving the outgoing cold accumulator is reduced to an amount smaller than that of the ingoing fresh gas undergoing treatment in the first or ingoing cold accumulator.

"ill

It is thus practicable to warm fully the ingoingor fresh gas cold accumulator without loss of cold the point at which it was introduced into the wet cooler is moved successively lower. In order to fully utilize the cold of the gaseous mixture, undergoing treatment, the gaseous stream leaving the wet cooler is divided and a major part passed through a cold accumulator in which cold is absorbed and a minor part through an indirect heat exchanger in which it passes in indirect heat exchange relation with refrigerating liquid which has been warmed and is on its return to the wet cooler.

In order to reheat the liquid the condenser, or wet cooler is provided with a plurality of fresh air inlets situated at various heights. While the fresh gas is quite cold it enters the condenser about the middle thereof and as the lower part of the accumulator becomes gradually warmer, the gas is lead step by step into the condenser at successively lower points so that only a fully heated gas flows into the lowermost portion of the condenser. The lower part of the condenser will therefore always remain warm and the sprinkling liquid supplied at the top end will leave the condenser at the bottom at the outside temperature.

, The accompanying drawing shows diagrammatically a preferred form of an apparatus for carrying out the improved process.

The apparatus comprises two cold accumulators b and b", a trickle condenser, or wet cooler J, a reversing valve 0, and a slide valve s.

Fresh gas at ordinary or room temperature enters through the valve 0 into the cold accumulator E), is cooled therein and partially freed from vapors. It then passes to the slide valve 8, and therefrom into the trickle cooler or'condenser through the top inlet (indicated by the arrow 1) The passage of fresh gas through the cold accumulator b continues until the lower end thereof is heated to room temperature or to the degree required by the process, and until the moisture condensed on the inner surfaces vaporpasses into the second cold accumultaor b",

where, after depositing its cold, it passes out through the valve 0 in a heated and dried condition.

The heated liquid which leaves the trickle cooler at the bottom may now be freed of any vapors absorbed from the gas by regeneration. For this purpose a part of the liquid, or the total amount of this liquid may be lead through a regenerator (not shown in the drawing).

A part of the stream of cold and dried gas leaving the trickle cooler f is divided, or branched off and flows in heat exchange relation with and countercurrent to the warmed refrigerating liquid in a countercurrent heat exchanger p, wherein it gives up its cold to such liquid passing through a coil.

After a reheating of the cold accumulator b has taken place, the stream of fresh ingoing gas is reversed by means of the valve 0. The gas now flows to the cold accumulator b which had been previously charged with cold by the outgoing dried gas and the process then proceeds in the same manner as before, only with a flow of gas in opposite direction. The cooled ingoing gas passes into the trickle cooler ,f first through the topmost inlet 1 of slide valve s and then as the temperature of the lower end of the cold accumulator 2)" increases successively or step by step at lower points of the condenser through the inlets 2, 3, 4 and 5.

The reversing valve 0 may preferably be actuated by a compressed air engine and the sliding valve 8 by a power liquid, such actuation being by means of controlling mechanisms not shown in the drawing. Flap valves m compel the gas to flow inside the trickle cooler from bottom to top. The arrows drawn in full lines show the direction of flow during the first, third, fifth, etc. blowing periods; dotted arrows show the reversed 105 direction during the second, fourth, sixth, etc. periods.

Brine, lye, alcohol or toluol, may be used as refrigerated liquids in accordance with the minimum temperature required for the separation and removal of vapors in the various cases; As a rule, vapors and frost separated from the treated gases, dissolve in the refrigerating liquid and have to be removed by regeneration. Cold expended or lostv in the process is replaced by a 115 separate refrigerating plant.

Water vapor may be separated from air and other gases quite cheaply by means of an ammonia refrigerating machine, as in such cases separation takes place at a temperature not below -30 C.; if however benzol vapors are to be separated from coke oven gas, or gases generated by other destructive distillation processes, minimum temperature's approaching 60 C. are required, and in case of carbon dioxide a temperature of 100 C. 125 and even lower is necessary.

In such cases the additional cold required may be generated by an expansion of compressed air or other compressed gases, which entails, a considerably higher expenditure of power.

Since certain changes in carrying out the above process and in the constructions set forth which embody the invention may be made without .departing from its scope, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

I claim:

1. A process for separating vapors from a gaseous mixture, which comprises passing a gaseous mixture through a cold yielding zone, continuing the passage of the gaseous mixture through the cold yielding zone until said zone has been warmed, bringing the gaseous mixture into con- 150 tact with a refrigerated brine in a wet cooler first at about a middle point and then as the gaseous mixture becomes warmer at successively lower points, and conducting outgoing gaseous mixture through a cold absorbing zone.

2. A process for separating vapors from a gaseous mixture, which comprises passing a gaseous mixture through a cold accumulator wherein the gaseous mixture is cooled by direct contact with chilled surfaces, bringing the cooled gaseous mixture into direct contact with a refrigerated brine in a wet cooler at successively lower points, and conducting said mixture thence through a second cold accumulator in which the cold is absorbed from the outgoing gas.

3. A process for separating vapors from a gaseous mixture, which comprises passing a gaseous mixture through a cold accumulator wherein the gaseous mixture is cooled by direct contact with chilled surfaces, bringing the cooled gaseous mix ture into direct contact with a refrigerated brine in a wet cooler at successively lower points, dividing the gaseous mixture issuing from the wet cooler and conducting one part through a cold accumulator and another part through a heat exchanger in indirect exchange relation with liquid medium.

i. A process for separating vapors from a gaseous mixture, whichcomprises passing a gaseous mixture through a cold accumulator wherein the gaseous mixture is cooled by direct contact with chilled surfaces, bringing the cooled gaseous mixture into direct contact with a refrigerated brine in a wet cooler at successively lower points, dividing the gaseous mixture issuing from the wet cooler and conducting a major part through a cold accumulator and a minor part through a heat exchanger in indirect exchange relation with an ingoing wet cooler liquid whereby said 6. An apparatus for separating vapors from a gaseous mixture, comprising in combination a plurality of cold accumulators, a reversing valve in communication with said accumulators, a wet cooler having a plurality of inlets between its middle portion and base, a slide valve adapted for successive communication with the wet cooler inlets, connecting conduits provided with flap valves between the cold accumulators, the wet cooler and the slide valve whereby gaseous mixture may be conducted to and from such members, an indirect countercurrent heat exchanger so connected with the wet cooler that a part of the outgoing gaseous mixture may be conducted therethrough, and a spray head within the wet cooler for introducing a refrigerating liquid thereinto.

7. A process for separating vapors from a gaseous mixture which comprises passing a gaseous mixture through a cold yielding zone with decreasein the amount of the cold available therein, bringing the thus cooled gaseous mixture into direct contact with a flowing refrigerated liquid by admitting said mixture at successively lower points in the path of the refrigerated liquid, and then conducting the cooled and dried mixture through a cold absorbing zone.

8. A process for separating vapors from a gaseous mixture which comprises passing a gaseous mixture through a cold yielding zone in which vapors carried by the gaseous mixture are separated as a deposit, and continuing the passage until said zone has become warm and the deposited vapors removed, bringing the thus cooled gaseous mixture into direct contact with a flow.- ing refrigerated liquid by admitting said mixture at successively lower points in the path of the refrigerated liquid, and then conducting the cooled and dried mixture through a cold absorbing zone.

9. An apparatus for separating vapors from a gaseous mixture comprising in combination a pluralityof cold accumulators, a wet cooler provided with a plurality of inlets positioned at the lower part and at one side thereof, a controlling means in communication with said inlets comprising a slide valve having ports which register with the inlets at successively lower points, and connections in operative relation with said cold accumulators and said wetcooler, one of said connections being through the controlling means and the inlets.

MATHIAS 

